Edexcel a level biology topic 4 exam questions and answer

Edexcel a level biology topic 4 exam questions and answer Describe what is meant by biodiversity. (2) - Answer-Variety of species in an ecosystem and the variety of alleles in a gene pool. Explain how the biodiversity of lemurs in two different parts of Madagascar could be compared. (3) - Answer-Record total number of species of lemur and total individuals within each species. Calculate an index of diversity for each location. The higher the index of diversity the greater biodiversity. gel electrophoresis/ dna profiling/molecular phylogeny/ protenomics In the 1970s, a theory for a new system of taxonomy was proposed by a scientist called Woese. Describe the process by which the scientific community critically evaluates new theories. (3) - Answer--communicating theory to scientific community. - peer review -checking evidence to ensure validity. (i) Suggest why successful interbreeding between chiffchaffs and willow warblers would make some scientists doubt their classification as separate species. (3) Suggest reasons why the two species do not interbreed (2) - Answer--successful interbreeding produces fertile offspring. -same species produce fertile offspring -due to e.g. genetic incompatability offspring of different species may be infertile. - reproductive isolation -different breeding times